Add color prop to CircularProgress

[Cheesy-Brik]

I think the color prop was most likely forgotten, as it's already in Chakra. So just adding this fixes it.

All Submissions:

• Have you followed the guidelines stated in CONTRIBUTING.md file?
• Have you checked to ensure there aren't any other open Pull Requests for the desired changed?

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

After these steps, you're ready to open a pull request.

a. Give a descriptive title to your PR.

Add color prompt from chakra CircularProgress to Pynecone
b. Describe your changes.
Adds a missing color prop that lets you change the color of the progress bar.

[picklelo]

Good catch!